Studies of morbidity associated with treatment for breast cancer are becoming increasingly important as clinical trials continue to document equivalent mortality rates for a variety of treatment options for breast cancer. Lymphedema has been identified by women experiencing it as one of the most distressing long-term consequences of breast cancer treatment. The objective of the proposed research is continue follow-up of a cohort of breast cancer patients to measure the incidence of upper extremity lymphedema, risk factors for its occurrence, and impact on quality of life in the 3rd to 5th years after diagnosis of breast cancer. The specific aims are to describe risk factors for and the time course of developing lymphedema, to systematically study progression, regression, or fluctuations of the disease, to assess changes in measures of quality of life as they relate to the diagnosis of lymphedema and its changes over time, and to test specific hypotheses about subgroups at particular risk of progression or exacerbation of lymphedema. A population-based random sample of 600 patients from Philadelphia and Delaware Counties, newly diagnosed with primary breast cancer from May, 1999 through September, 2001, is being followed with 3 interviews over two years for the parent study. The proposed study will continue this follow-up with 4 more interviews at nine month intervals up to 5 years post diagnosis. Medical records are reviewed to obtain clinical data regarding characteristics of the disease at diagnosis, treatment modality, and recurrence. Lymphedema will be assessed with a questionnaire that we have developed and validated for this study; arm measurements will also be performed for continued validation. Potential patient-, disease-, and treatment-related risk factors for lymphedema, and both disease-specific and general quality of life measurements will be made at each time point. Lymphedema risk over time will be modeled as a function of patient characteristics at baseline and during the course of the study. Continued review of the literature reinforces the uniqueness of this study in terms of its population base, its size, inclusion of minority women, and the wealth of information on risk factors and their timing with respect to the occurrence of lymphedema. Preliminary data from the parent study suggest that only longer follow-up can capture the interplay of time-dependent risks, ongoing treatment, and patient characterisitics that occur over a longer period of time.